Protective Efficacy of a Recombinant Bacterial Artificial Chromosome Clone of a Very Virulent Marek's Disease Virus Containing a Reticuloendothelial Virus Long Terminal Repeat.

Protective Efficacy of a Recombinant Bacterial Artificial Chromosome Clone of a Very Virulent Marek's Disease Virus Containing a Reticuloendothelial Virus Long Terminal Repeat. Avian Pathol. 2016 Jun 3;:1-31 Authors: Mays JK, Black-Pyrkosz A, Spatz S, Fadly AM, Dunn JR Abstract Marek's disease virus (MDV), an alphaherpesvirus, causes Marek's disease (MD), a lymphoproliferative disease in poultry characterized by T-cell lymphomas, nerve lesions and mortality. Vaccination is used worldwide to control MD, but increasingly virulent field strains can overcome this protection, driving a need to create new vaccines. Previous studies revealed that insertion of reticuloendotheliosis virus (REV) long-terminal repeat (LTR) into a bacterial artificial chromosome (BAC) clone of a very virulent strain of MDV, Md5 rendered the resultant recombinant virus, rMd5 REV-LTR BAC, fully attenuated in maternal antibody positive (Mab+) chickens at passage 40. In the current study, the protective efficacy of rMd5 REV-LTR BAC was evaluated. First, passage 70 was identified as being fully attenuated in Mab- chickens and chosen as the optimal passage level for use in protective efficacy studies. Second, three protective efficacy trials were conducted comparing the rMd5 REV-LTR p70 BAC to the CVI988/Rispens vaccine. Groups of Mab+ and Mab- 15I5×71 chickens were vaccinated in ovo at 18 days of embryonation or intra-abdominally at day of hatch, and challenged at 5...
Source: Avian Pathology - Category: Pathology Authors: Tags: Avian Pathol Source Type: research